The present invention relates to a power transmission mechanism for a vehicle, and more particularly to a power transmission mechanism which is suitable for the composition or distribution of the power obtained from a plurality of power generators, and to a vehicle provided with such power transmission mechanism.
Recently, the hybrid vehicle mounted with both an internal combustion engine and an electric motor is coming to attract the public attention. Although the hybrid vehicle is available in various forms, a first prior art is one designed to distribute the mechanical power produced by an internal combustion engine by means of a differential gear mechanism. An example of the differential gear mechanism includes the planetary gear mechanism, which comprises three input gears, namely the sun gear, the carrier and the ring gear; it is characteristic, however, that the number of revolution of one shaft serves as a weighted additional factor to the number of revolution of each of two other shafts. Where it is designed that the traveling speed of a vehicle is defined by the primary combination of the number of revolution of an engine and the number of revolution of an electric motor, it becomes possible to let an engine operate at the optimal number of revolution at all times, regardless of the traveling speed of a vehicle, by controlling the number of the revolution of an electric motor. This example is disclosed in Japanese Patent Laid-Open No. 7-336810. The scheme disclosed is advantageous in that the size of a vehicle can be made compact as a hybrid vehicle because the mechanical speed change gear can be omitted.
Besides the above prior art, there is a second prior art disclosed by Japanese Patent Laid-Open No. 11-301291. This prior art relates to a speed change gear designed for distributing the energy of the driving power source among a plurality of differential gear mechanisms, as well as for synthesizing the energies outputted from a plurality of electric motors, respectively connected with the plurality of differential gear mechanisms, and those outputted from the plurality of differential gear mechanisms. This art, when compared with the first prior art, provides a wider speed change range where the size of the electric motor is fixed. This provides an advantage that the performance of the vehicle can be improved.
On the other hand, however, this prior art gives rise to a problem that the vehicle drive mechanism using a plurality of differential gears is accompanied by the increase in the number of times of gear meshing operation and resulting increase in the mechanical loss. A first object of the present invention is to control the mechanical loss of a vehicle having a plurality of differential gears to a minimum.
Incidentally, as discussed previously, the planetary gear has the characteristic suitable for the use on the hybrid vehicle. However, in general, it is difficult to satisfy the conditions for obtaining a desired gear ratio of the planetary gear mechanism and thus it is not always possible to obtain the desired gear ratio. A second object of the present invention is to realize a power transmission mechanism having a design freedom that is wide enough to provide a desired gear ratio and applicable to the hybrid vehicle with an electric speed change mechanism having a wide speed change range.
The present invention provides a vehicle provided with a composite power transmission mechanism, said mechanism including: a first shaft that is rotated by a planetary gear; and second, third, and fourth shafts that are rotated respectively by gears directly meshing with the planetary gear; wherein the first shaft is connected with a driving shaft of the vehicle; the second shaft is connected with an engine; and the third shaft and the fourth shaft are connected respectively with an electric rotary machine.
The driving shaft of the vehicle is made to revolve by means of the planetary gear of the composite power transmission mechanism, and the planetary gear is capable of transmitting the power of respective driving power sources, i.e., the electric rotary machine and the engine to each other, when the gears are meshed once with one another, so that the mechanical loss resulting from the meshing of the gears can be controlled to a minimum.
Further, the present invention provides a composite power transmission mechanism for a vehicle including at least three mechanical power generators and corresponding output shafts, wherein the composite power transmission mechanism includes a sun gear A, a sun gear B, a revolution gear A, a revolution gear B and an internal gear; the sun gear A, the revolution gear A and the internal gear A constitute a planetary gear mechanism; the revolution gear B is connected with the revolution gear A so as to rotate about its own axis and to revolve at the same speed as the revolution gear A; the revolution gear B meshes with the sun gear B: the sun gear A, the sun gear B and the internal gear are connected respectively with the mechanical power generator either directly or through a mechanical power transmission mechanism; and a carrier of the planetary gear mechanism and the output shaft are connected with each other either directly or through the mechanical power transmission mechanism.
The present invention provides a composite power transmission mechanism for a vehicle including at least three mechanical power generators and corresponding output shafts, wherein the composite power transmission mechanism includes a sun gear A, a sun gear B, a sun gear C, a revolution gear A, a revolution gear B, a revolution gear C and a carrier; the sun gear A meshes with the revolution gear A: the sun gear B meshes with the revolution gear B; the sun gear C meshes with the revolution gear C; the revolution gear A, the revolution gear B and the revolution gear C are connected with one another so as to rotate about their own axes at the same speed; the carrier holds the revolution gear A, the revolution gear B and the revolution gear C so as to enable these gears to revolve at the same speed; the sun gear A, the sun gear B and the sun gear C are connected respectively with the mechanical power generator; and the carrier is connected with the output shaft either directly or through a mechanical power transmission mechanism.
The present invention provides a composite power transmission mechanism for a vehicle including at least three mechanical power generators and corresponding output shafts, wherein the composite power transmission mechanism includes a sun gear A, a sun gear B, a sun gear C, a revolution gear A, a revolution gear B, a revolution gear C, an intermediary revolution gear and a carrier; the sun gear A meshes with the revolution gear A; the sun gear B meshes with the revolution gear B; the sun gear C meshes with the revolution gear C through the intermediary revolution gear; the revolution gear A, the revolution gear B and the revolution gear C are connected with one another so as to rotate about their own axes at the same speed; the carrier holds the revolution gear A, the revolution gear B, the revolution gear C and the intermediary gear so as to enable these gears to revolve at the same speed; the sun gear A, the sun gear B and the sun gear C are connected respectively with the mechanical power generator either directly or through a mechanical power transmission mechanism; and the carrier is connected with the output shaft either directly or through the mechanical power transmission mechanism.
The present invention provides a composite power transmission mechanism for a vehicle including at least three mechanical power generators and corresponding output shafts, wherein the composite power transmission mechanism includes a sun gear A, a sun gear B, a revolution gear A, a revolution gear B, an intermediary revolution gear and an internal gear; the sun gear A, the revolution gear A, the intermediary gear and the internal gear constitute a double pinion planetary gear mechanism; the composite power transmission mechanism includes the revolution gear B that is connected with the revolution gear A so as to rotate about its own axis and to revolve at the same speed as the revolution gear A; the revolution gear B meshes with the sun gear B; the sun gear A, the sun gear B and the internal gear are connected respectively with the mechanical power generator either directly or through a mechanical power transmission mechanism; a carrier of the double pinion planetary gear mechanism is connected with the output shaft either directly or through the mechanical power transmission mechanism.
The present invention provides a composite power transmission mechanism including at least three mechanical power generators and corresponding output shafts, wherein the composite power transmission mechanism includes a sun gear A, a sun gear B, a revolution gear A, a revolution gear B, an intermediary revolution gear A, an intermediary revolution gear B and an internal gear; the sun gear A, the revolution gear A, the intermediary revolution gear and the internal gear constitute a double pinion planetary gear mechanism; the composite power transmission mechanism includes the revolution gear B that is connected with the revolution gear A so as to rotate about its own axis and to revolve at the same speed as the revolution gear A; the revolution gear B meshes with the sun gear B through the intermediary revolution gear B; the sun gear A, the sun gear B and the internal gear are connected respectively with the mechanical power generator either directly or through a mechanical power transmission mechanism; and a carrier of the double pinion planetary gear mechanism is connected with the output shaft either directly or through the mechanical power transmission mechanism.
The present invention provides, in a composite power transmission mechanism including at least three mechanical power generators and corresponding mechanical output shafts, wherein the rotating speed, xcfx89i (i=1, 2, . . . ), of each of the mechanical power generators is expressed as xcfx89i=keixc2x7xcfx89e+kvixc2x7xcfx89v (i=1, 2, . . . ; kei ? 0; kvi ? 0) where xcfx89e=the rotating speed of each mechanical power generator and xcfx89v=the rotating speed of each of the mechanical output shafts, composite power transmission means in which the composite power transmission mechanism includes a sun gear A, a sun gear B, a revolution gear A, a revolution gear B and a carrier; the revolution gear A and the revolution gear B rotate about their own axes at the same speed; the revolution gear A and the revolution gear B are connected respectively with the carrier so as to revolve at the same speed; and the revolution gear A meshes with the sun gear A; and the revolution gear B meshes with the sun gear B.